Air Mom

Alright, listen up, nimrod. The joke is that the first person tries to insult an orphan by saying they did the nasty with their mom. But, plot twist, orphans don't HAVE moms in their lives anymore, so the orphan hits back with a zinger about the first person hooking up with thin air. It's funny because it's unexpected and makes the first person look like a total tool. Also, your IQ is showing.